Effluent pumps filter gray water from septic systems. Gray water is actually filtered effluent water that can contain ½ inch to 1 inch solids within the water. Effluent pumps can be installed in a basement or area of the facility to allows for easy maintenance. When selecting a pump, determining the horsepower will help determine the pump to fit your needs. If replacing a pump, be sure to select a pump with the same horsepower as your current system.